Worst West Nile outbreak on record strikes US

Gambusia affinis, more commonly known as "mosquito fish," are seen swimming on June 29, 2012 after being released in a neglected pool infested with mosquitoes at a foreclosed home in Pleasant Hill, California. The Contra Costa County Mosquito and Vector Control District has used mosquito fish and BVA Larvacide oils to eradicate the pest.

The reported 1,118 cases and 41 deaths due to the mosquito-borne illness represent the highest annual toll ever seen from the virus through the third week of August, the CDC said. Nearly half of the cases have been reported in Texas, with the southern states of Mississippi, Louisiana, South Dakota, and Oklahoma also heavily affected.

Nearly every US state has reported West Nile infections in people, birds, or mosquitoes during 2012. The disease is typically spread by mosquitoes, though transmission through blood transfusions, organ transplants, breastfeeding or from mother to child during pregnancy are occasionally seen, according to the CDC.

Lyle Petersen, the director of the CDC's Vector-Borne Infectious Disease Division, told CNN that West Nile epidemics usually peak in mid-August, "but it takes a couple of weeks for people to get sick, go to the doctor and get reported." He added, "Thus we expect many more cases to occur."

Reuters noted that the rate of infection rate has jumped more than 60 percent over the past week, with over 400 new cases and 15 new deaths reported.

How can you avoid West Nile? Some basic steps are highly effective. The CDC recommends using bus repellent to deter mosquitoes, screening windows, and getting rid of containers that could hold standing water, where mosquitoes breed.